NEW DELHI (Reuters) - India started field trials to buy 126 fighter jets this week, defence officials said on Friday, moving forward on a $10.4 billion deal to modernise the air force. Boeings F/A-18 Super Hornet, Frances Dassault Rafale, Lockheed Martin Corps F-16, Russias MiG-35, Swedens Saab JAS-39 Gripen and the Eurofighter Typhoon, produced by a consortium of European companies, are in the race for the contract, one of the biggest in play. The trials have begun in full swing and it will take a year to complete it in different places and weather conditions, Nung Sanglemba Ao, a defence ministry official, told Reuters. This week, two pilots are flying Boeings Super Hornets in the southern city of Bangalore to test the planes manoeuvrability and effectiveness, defence officials said. The aircraft will be tested in extreme cold conditions in the Himalayas and the hot and humid deserts of Rajasthan, an air force spokesman said. India is one of the worlds biggest arms importers, and its government plans to spend more than $30 billion over the next five years to upgrade its largely Soviet-era arsenal to counter potential threats from Pakistan and China. Lockheed last year sold six C-130J military transport planes to India for about $1.1 billion, while Boeing has already sealed a $2.1 billion deal to sell eight maritime patrol aircraft.